1. Field of the Invention
The invention relates to the field model aircraft. More particularly, the invention relates to controls for ailerons, flaps, and engines for radio-controlled model aircraft.
2. Description of the Prior Art
Flying radio-controlled model aircraft (RC aircraft) is a popular activity. The typical RC aircraft has a variety of flight-control means that include one or more propellers and various control surfaces, such as ailerons, wing flaps, a rudder, and elevators. RC aircraft come in many different designs, weights. Some RC aircraft are equipped with all the flight-control means just mentioned, others have just a propeller and a rudder. Some are well-balanced and relatively easy to fly, others require a great deal of skill in controlling the various flight-control means. To operate the flight-control means, a radio receiver (RX) is generally installed inside the body or the fuselage of the RC aircraft. The operator sends a radio signal to the RX from a corresponding radio transmitter (TX) that has a control panel. The RX converts the signal to a voltage and feeds it to a particular servo-controller, which actuates a mechanical lever or other mechanism to operate a particular flight-control means. For example, after the RC aircraft has been launched into the air, the operator manipulates the controls on the control panel to control the speed of the propeller, raise or lower ailerons, elevators, or wing flaps, or move the rudder to the left or right.
Many of the flight-control means on the RC aircraft are groups of individual control surfaces or engines. If the aircraft is equipped with ailerons, it will have two or
Many of the flight-control means on the RC aircraft are groups of individual control surfaces or engines. If the aircraft is equipped with ailerons, it will have two or four of them. It is not unusual for an RC aircraft to have four motor-driven propellers. For purposes of illustration, a flight-control means that comprises multiple control surfaces or multiple engines is referred to hereinafter as a flight-control means group (FCM group) and each individual control surface or engine is referred to as an individual flight-control means (individual FCM). With conventional radio control systems, a servo-motor, referred to simply as servo hereinafter, is provided to each individual FCM in the RC aircraft. Thus, for example, in an RC aircraft with four engines driving the propellers, four servos are provided, each servo connected to a linkage that controls an engine. If the RC aircraft has four ailerons, four additional servos are provided, each one controlling one aileron. A typical RC aircraft has three FCM groups: a first group including four ailerons; a second group including two wing flaps, and a fourth group including four motor-drivin propellers. Thus, it has ten servos to control the ten individual FCMs, rather than three servos to control the three FCM groups. Providing a separate servo for each one of a group of similar FCMs has several disadvantages. For one, a greater number of servos must be installed in the aircraft. This requires space and effort to install the additional devices, as well as the higher acquisition costs. The primary disadvantage, however, is one of aircraft control and safety. The failure of one servo to an individual one of a FCM group inevitably causes the aircraft to become unbalanced, making it difficult, if not impossible, to control and guide the aircraft to a non-catastrophic landing. If a servo to an aileron fails, it is much easier to guide an RC aircraft to a safe landing if all ailerons are in the same position, i.e., the failed position, than if one is stuck in the failed position, while the other three move to the control position.
For the reasons cited above, what is needed is an RC aircraft control system that provides a single control for a FCM group. What is further needed is such a control system that reduces the number of servos required to control the various FCMs and also reduces the cost and effort of installing the FCM.